I have been again struggling to fix web-streaming trouble in “motion” tool.
In motion.conf file, stream_port 8081 is designated but accessing that port does not start streaming movie at all though the control port of 8080 well functions.
USB camera has no defect nor malfunction as I confirmed it working in Windows10 PC.
Need to check if motion.conf describes as “webcam_localhost off” or not.
Finally I found a mis-configuration here:
# Restrict stream connections to localhost only (default: on)
stream_localhost off
It was set as “on” thus streaming movie is not shown in other browser except localhost.